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7Network Working Group                                          A. Newton
8Request for Comments: 3663                                VeriSign, Inc.
9Category: Experimental                                     December 2003
10
11
12                       Domain Administrative Data
13            in Lightweight Directory Access Protocol (LDAP)
14
15Status of this Memo
16
17   This memo defines an Experimental Protocol for the Internet
18   community.  It does not specify an Internet standard of any kind.
19   Discussion and suggestions for improvement are requested.
20   Distribution of this memo is unlimited.
21
22Copyright Notice
23
24   Copyright (C) The Internet Society (2003).  All Rights Reserved.
25
26Abstract
27
28   Domain registration data has typically been exposed to the general
29   public via Nicname/Whois for administrative purposes.  This document
30   describes the Referral Lightweight Directory Access Protocol (LDAP)
31   Service, an experimental service using LDAP and well-known LDAP types
32   to make domain administrative data available.
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60RFC 3663           Domain Administrative Data in LDAP      December 2003
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63Table of Contents
64
65   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
66       1.1.  Historical Directory Services for Domain Registration
67             Data . . . . . . . . . . . . . . . . . . . . . . . . . .  3
68       1.2.  Motivations. . . . . . . . . . . . . . . . . . . . . . .  3
69       1.3.  Abbreviations Used . . . . . . . . . . . . . . . . . . .  4
70   2.  Service Description. . . . . . . . . . . . . . . . . . . . . .  4
71   3.  Registry LDAP Service. . . . . . . . . . . . . . . . . . . . .  6
72       3.1.  TLD DIT. . . . . . . . . . . . . . . . . . . . . . . . .  6
73             3.1.1.  DIT Structure. . . . . . . . . . . . . . . . . .  6
74             3.1.2.  Allowed Searches . . . . . . . . . . . . . . . .  7
75             3.1.3.  Access Control . . . . . . . . . . . . . . . . .  7
76       3.2.  Name Server DIT. . . . . . . . . . . . . . . . . . . . .  8
77             3.2.1.  DIT Structure. . . . . . . . . . . . . . . . . .  8
78             3.2.2.  Allowed Searches . . . . . . . . . . . . . . . .  8
79       3.3.  Registrar Referral DIT . . . . . . . . . . . . . . . . .  9
80             3.3.1.  DIT Structure. . . . . . . . . . . . . . . . . .  9
81   4.  Registrar LDAP Service . . . . . . . . . . . . . . . . . . . . 10
82       4.1.  TLD DIT. . . . . . . . . . . . . . . . . . . . . . . . . 10
83             4.1.1.  DIT Structure. . . . . . . . . . . . . . . . . . 10
84             4.1.2.  Allowed Searches . . . . . . . . . . . . . . . . 11
85             4.1.3.  Access Control . . . . . . . . . . . . . . . . . 11
86       4.2.  Name Server and Contact DIT. . . . . . . . . . . . . . . 12
87             4.2.1.  DIT Structure. . . . . . . . . . . . . . . . . . 12
88             4.2.2.  Allowed Searches . . . . . . . . . . . . . . . . 13
89   5.  Clients. . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
90   6.  Lessons Learned. . . . . . . . . . . . . . . . . . . . . . . . 14
91       6.1.  Intra-Server Referrals . . . . . . . . . . . . . . . . . 14
92       6.2.  Inter-Server Referrals . . . . . . . . . . . . . . . . . 15
93       6.3.  Common DIT . . . . . . . . . . . . . . . . . . . . . . . 15
94       6.4.  Universal Client . . . . . . . . . . . . . . . . . . . . 16
95       6.5.  Targeting Searches by Tier . . . . . . . . . . . . . . . 16
96       6.6.  Data Mining. . . . . . . . . . . . . . . . . . . . . . . 16
97   7.  IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 16
98   8.  Internationalization Considerations. . . . . . . . . . . . . . 16
99   9.  Security Considerations. . . . . . . . . . . . . . . . . . . . 17
100   10. Intellectual Property Statement. . . . . . . . . . . . . . . . 17
101   11. Normative References . . . . . . . . . . . . . . . . . . . . . 18
102   Appendix A.  Other Work. . . . . . . . . . . . . . . . . . . . . . 19
103   Appendix B.  Acknowledgments . . . . . . . . . . . . . . . . . . . 19
104   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 20
105   Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 21
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118
1191.  Introduction
120
121   This document describes the Referral Lightweight Directory Access
122   Protocol (LDAP) Service, an experimental project launched by
123   VeriSign, Inc., to explore the use of LDAP and LDAP-related
124   technologies for use as a directory service of administrative domain
125   registration information.
126
1271.1.  Historical Directory Services for Domain Registration Data
128
129   The original National Science Foundation contract for the InterNIC
130   called for the creation of an X.500 directory service for the
131   administrative needs of the domain registration data and information.
132   Due to problems with implementations of X.500 server software, a
133   server based on the Nicname/Whois [1] protocol was temporarily
134   erected.
135
136   In 1994, the Rwhois [3] protocol was introduced to enhance the
137   Nicname/Whois protocol.  This directory service never gained wide
138   acceptance for use with domain data.
139
140   Presently, ICANN requires the operation of Nicname/Whois servers by
141   registries and registrars of generic Top-Level Domains (TLD's).
142
1431.2.  Motivations
144
145   With the recent split in functional responsibilities between
146   registries and registrars, the constant misuse and data-mining of
147   domain registration data, and the difficulties with machine-
148   readability of Nicname/Whois output, the creation of the Referral
149   LDAP Service had the following motivations:
150
151   o  Use a mechanism native to the directory protocol to refer clients
152      from inquiries about specific domains made at a registry to the
153      appropriate domain within the appropriate directory service at a
154      registrar.
155
156   o  Limit access to domain data based on authentication of the client.
157
158   o  Provide structured queries and well-known and structured results.
159
160   o  Use a directory service technology already in general use.
161
162   Given these general criteria, LDAP [5] was selected as the protocol
163   for this directory service.  The decision was also made to restrict
164   the use of LDAP to features most readily available in common
165   implementations.  Therefore, a goal was set to not define any new
166   object classes, syntaxes, or matching rules.
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175   The experiment was successful in exploring how LDAP might be used in
176   this context and demonstrating the level of customization required
177   for an operational service.  Conclusions and observations about this
178   experiment are outlined in Section 6.
179
1801.3.  Abbreviations Used
181
182   The following abbreviations are used to describe the nature of this
183   experiment:
184
185      TLD: Top-Level Domain.  Refers to the domain names just beneath
186      the root in the Domain Name System.  This experiment used the
187      TLD's .com, .net, .org, and .edu.
188
189      SLD: Second-Level Domain.  Refers to the domain names just beneath
190      a TLD in the Domain Name System.  An example of such a domain name
191      would be "example.com".
192
193      DIT: Directory Information Tree.  One of many hierarchies of data
194      entries in an LDAP server.
195
196      DN: Distinguished Name.  The unique name of an entry in a DIT.
197
198      cn: common name.  See RFC 2256 [7].
199
200      dc: domain component.  See RFC 2247 [4].
201
202      uid: user id.  See RFC 2798 [9].
203
2042.  Service Description
205
206   The service is composed of three distinct server types: a registry
207   LDAP server, registrar LDAP servers, and registrant LDAP servers.
208
209   The registry LDAP server contains three Directory Information Trees
210   (DIT's).
211
212   o  The Top-Level Domain DIT's follow the DNS hierarchy for domains
213      (e.g., dc=foo,dc=com).
214
215   o  The name server DIT allows a view of the name servers, many of
216      which serve multiple domains.
217
218   o  The registrar-referral DIT provides referrals from the registry
219      into the respective TLD DIT of the registrars (on a TLD basis).
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231   The registrar LDAP server contains two types of DIT's.
232
233   o  The TLD DIT follows the DNS hierarchy for domains (e.g.,
234      dc=foo,dc=com) and parallels the TLD DIT of the registry.
235
236   o  The name server and contact DIT allow a view of the name servers
237      and contacts, many of which are associated and serve multiple
238      domains.
239
240   There is no specification on the DIT or schema for the registrant
241   LDAP server.  Referrals from the registrar server to the registrant
242   server are provided solely for the purpose of allowing the registrant
243   direct control over extra administrative information as it relates to
244   a particular domain.
245
246   Access control for this service is merely a demonstration of using a
247   Distinguished Name (DN) and password.  Should registries and
248   registrars uniformly adopt LDAP as a means to disseminate domain
249   registration data, standardization of these DN's would need to be
250   undertaken based on each type of user base.
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2873.  Registry LDAP Service
288
2893.1.  TLD DIT
290
2913.1.1.  DIT Structure
292
293   The registry TLD DIT has the following structural hierarchy:
294
295                          TLD (e.g., dc=net)
296                                  |
297                                  |
298               -------------------------------------
299               |                                   |
300      SLD (e.g., dc=foo,dc=net)           SLD (e.g., dc=bar,dc=net)
301               |                                   |
302       ---------------------            ---------------------
303       |           |       |            |           |       |
304   name server     |       |        name server     |       |
305   (e.g.,          |       |        (e.g.,          |       |
306   cn=nameserver1, |       |        cn=nameserver1, |       |
307   dc=foo,dc=net ) |       |        dc=bar,dc=net ) |       |
308                   |       |                        |       |
309          name server      |               name server      |
310          (e.g.,           |               (e.g.,           |
311          cn=nameserver2,  |               cn=nameserver2,  |
312          dc=foo,dc=net )  |               dc=bar,dc=net )  |
313                           |                                |
314                registrar referral               registrar referral
315                (e.g.,                           (e.g.,
316                cn=registrar,                    cn=registrar,
317                dc=foo,dc=net )                  dc=bar,dc=net )
318
319
320                    Figure 1: Registry DIT Overview
321
322   The root of a TLD DIT is an entry of objectclass domain as specified
323   by RFC 2247 [4] and represents a top-level domain.
324
325   The second tier of the DIT represents second-level domains.  Each of
326   these entries is of objectclass domain as specified by RFC 2247 [4].
327   The description attribute on these entries often contains descriptive
328   text giving the name of the registrar through which these domains
329   have been registered.
330
331   The third tier contains entries specific to each second-level domain.
332   Name server entries are of objectclass ipHost as specified by RFC
333   2307 [8].  The distinguished names of these name server entries are
334   algorithmically calculated, where the first component is the word
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343   "nameserver" concatenated with an index number of the name server
344   entry and the remaining components are the appropriate domain names.
345   There is no specification relating the value of the name server entry
346   to the index it may be assigned other than it is unique and
347   consistent with respect to the client session.  This tier also
348   contains the referral from the registry to the registrar.  This
349   referral is a direct referral to the entry in the appropriate
350   registrar LDAP server corresponding to the domain name that the
351   referral falls beneath in this DIT.
352
3533.1.2.  Allowed Searches
354
355   Because of the vast number of entries contained within this DIT, only
356   certain types of searches are allowed.  Allowing any search
357   expressible via LDAP would lead to expensive searches that would be
358   far too costly for a publicly available service.  The searches
359   allowed are as follows:
360
361   o  One-level scoped searches based at the root of the DIT.  Substring
362      matching is allowed on dc attributes, but the substring must be at
363      least be 3 characters in length.
364
365   o  Base search based at the root of the DIT.
366
367   o  Base, one-level, and sub-tree searches based at any second level
368      domain name (the second tier) and below.
369
3703.1.3.  Access Control
371
372   The registry TLD DIT only has one access control type.  When a client
373   binds with a DN of "cn=trademark" and password of "attorney", the
374   second-level domain entries also take on an objectclass of
375   extensibleObject with the added attributes of "createddate" and
376   "registrationexpirationdate", which are of type Generalized Time, as
377   specified by RFC 2252 [6].
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3993.2.  Name Server DIT
400
4013.2.1.  DIT Structure
402
403   The registry name server DIT has the following structural hierarchy:
404
405                         (o=nsiregistry.com)
406                                  |
407                                  |
408               -------------------------------------
409               |                  |                |
410           name server        name server      name server
411         (cn=ns1.foo.net)   (cn=ns.bar.com)  (cn=named.acme.org)
412
413
414                    Figure 2: Registry DIT Overview
415
416   The root of a name server DIT is an entry of objectclass organization
417   as specified by RFC 1617 [2].  It has no significance other than to
418   serve as the root of the DIT.
419
420   The second tier of this DIT represents name servers.  Each of these
421   entries is of objectclass ipHost, as specified by RFC 2307 [8].
422
4233.2.2.  Allowed Searches
424
425   Because of the vast number of entries contained within this DIT, only
426   certain types of searches are allowed.  Allowing any search
427   expressible via LDAP would lead to searches far too costly for a
428   publicly available service.  The searches allowed are as follows:
429
430   o  One-level and sub-tree scoped searches based at the root of the
431      DIT if a filter on the cn attribute is provided.
432
433   o  Base search based at the root of the DIT.
434
435   o  Base, one-level, and sub-tree searches based at any name server
436      entry.
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4553.3.  Registrar Referral DIT
456
4573.3.1.  DIT Structure
458
459   The registry registrar-referral DIT has the following structural
460   hierarchy:
461
462                        (o=tlds)
463                           |
464                           |
465            -------------------------------
466            |         |         |         |
467           tld       tld       tld       tld
468         (dc=net)  (dc=com)  (dc=org)  (dc=edu)
469            |         |         |         |
470            :         :         |         :
471            :         :         |         :
472                                |
473                   ---------------------------
474                   |            |            |
475               referral to  referral to  referral to
476               registrar 1  registrar 2  registrar n
477               dc=org DIT   dc=org DIT   dc=org DIT
478
479
480                Figure 3: Registry Referral DIT Overview
481
482   The root of the registrar referral DIT is an entry of objectclass
483   organization, as specified by RFC 1617 [2].  It has no significance
484   other than to serve as the root of this DIT.
485
486   The second tier of this DIT represents top-level domains.  Each of
487   these entries is of objectclass domain, as specified by RFC 2247 [4].
488
489   Underneath each TLD entry, the third tier contains referrals to the
490   appropriate TLD DIT of each registrar.
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510
5114.  Registrar LDAP Service
512
5134.1.  TLD DIT
514
5154.1.1.  DIT Structure
516
517   The registrar TLD DIT, which is similar to the registry TLD DIT, has
518   the following structural hierarchy:
519
520                          TLD (e.g., dc=net)
521                                  |
522                                  |
523               ------------------------------------------------
524               |                                          |   |
525      SLD (e.g., dc=foo,dc=net)                           :   :
526               |                                          :   :
527       ---------------------------------------------
528       |                        |                  |
529       |                        |                  |
530   name server            contact             referral to
531   (e.g., cn=nameserver1, (e.g., cn=contact1, registrant
532   dc=foo,dc=net       )  dc=foo,dc=net    )
533       |
534       |
535   name server contact
536   (e.g., cn=contact,
537   cn=nameserver1,
538   dc=foo,dc=net     )
539
540                    Figure 4: Registrar DIT Overview
541
542   The root of a TLD DIT is an entry of objectclass domain, as specified
543   by RFC 2247 [4] and represents a top-level domain.
544
545   The second tier of the DIT represents second-level domains.  Each of
546   these entries is of objectclass domain, as specified by RFC 2247 [4].
547
548   The third tier contains entries specific to each second-level domain.
549   The entries at this level are as follows:
550
551   o  Name server entries are of objectclass ipHost, as specified by RFC
552      2307 [8].  The distinguished names of these name server entries
553      are algorithmically calculated where the first component is the
554      word "nameserver" concatenated with an index number of the name
555      server entry and the remaining components are the appropriate
556      domain names.  There is no specification relating the value of the
557      name server entry to the index it may be assigned other than it is
558      unique and consistent with respect to the client session.
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567   o  Contact entries are of objectclass inetOrgPerson, as specified by
568      RFC 2798 [9].  The distinguished names of these contact entries
569      are algorithmically calculated, where the first component is the
570      word "contact" concatenated with an index number of the contact
571      and the remaining components are the appropriate domain names.
572      There is no specification relating the value of the contact entry
573      to the index it may be assigned other than it is unique and
574      consistent with respect to the client session.  The description
575      attribute of the entry contains the role for which a contact is
576      related to a domain.  These roles are identified as "Admin
577      Contact", "Technical Contact", and "Billing Contact", and may
578      appear in any order.
579
580   o  Finally, this third tier contains the referral from the registrar
581      to the registrant.
582
583   The fourth tier only contains name server contact entries.  These
584   entries are of objectclass inetOrgPerson, as specified by RFC 2798
585   [9].
586
5874.1.2.  Allowed Searches
588
589   Because of the vast number of entries contained within this DIT, only
590   certain types of searches are allowed.  Allowing any search
591   expressible via LDAP would lead to searches far too costly for a
592   publicly available service.  The searches allowed are as follows:
593
594   o  One-level scoped searches based at the root of the DIT.  Substring
595      matching is allowed on dc and o attributes, but the substring must
596      be at least 3 characters in length.
597
598   o  Base search based at the root of the DIT.
599
600   o  Base, one-level, and sub-tree searches based at any second level
601      domain name (the second tier) and below.
602
6034.1.3.  Access Control
604
605   The registrar TLD DIT has two access control types.  When binding
606   anonymously, a client only sees dc, o, and c attributes of the
607   second-level domain entries.  When a client binds with a DN of
608   "cn=trademark" and password of "attorney", all of the other
609   attributes normally available on entries of objectclass domain are
610   visible if they have values.  In addition, if a client binds with the
611   DN of a contact and password of "password", all attributes for
612   second-level domain entries for which the bind DN has a relation are
613   visible.
614
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6234.2.  Name Server and Contact DIT
624
6254.2.1.  DIT Structure
626
627   The registrar name server and contact DIT has the following
628   structural hierarchy:
629
630                             (o=nsi.com)
631                                  |
632                                  |
633               --------------------------------------
634               |                                    |
635            Contacts                           Name Servers
636          (ou=contacts)                     (ou=name servers)
637               |                                    |
638        -----------------                ------------------------
639        |             | |                |                    | |
640     Contact          : :            Name Server              : :
641   (uid=handle)       : :            (cn=handle)              : :
642                                         |
643                                     Name Server
644                                       Contact
645                                     (cn=contact1)
646
647                    Figure 5: Registrar DIT Overview
648
649   The first tier of the name server and contact DIT is an entry of
650   objectclass organization, as specified by RFC 1617 [2].
651
652   The second tier of the DIT contains two entries, each of which is of
653   objectclass organizationalUnit, as specified by RFC 2256 [7].  One
654   entry represents the part of the DIT containing contacts and the
655   other entry represents the part of the DIT containing name servers.
656
657   Entries underneath the contacts organizationalUnit entry are of
658   objectclass inetOrgPerson and represent contacts registered with the
659   registrar.  Their RDN is composed of the uid attribute.  The uid
660   attribute's value is a unique identifier or handle that is registrar
661   assigned.
662
663   Entries underneath the name server organizationalUnit entry are of
664   objectclass ipHost and represent name servers registered with the
665   registrar.  Their RDN is composed of the cn attribute.  The cn
666   attribute's value is a unique identifier or handle that is registrar
667   assigned.  Each name server entry may optionally have children
668   entries of objectclass inetOrgPerson.  These entries represent the
669   contacts of the name server they fall beneath.
670
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6794.2.2.  Allowed Searches
680
681   Because of the vast number of entries contained within this DIT, only
682   certain types of searches are allowed.  Allowing any search
683   expressible via LDAP would lead to searches far too costly for a
684   publicly available service.  The searches allowed are as follows:
685
686   o  One-level and base searches at the root of the DIT.
687
688   o  Sub-tree searches at the root of the DIT using cn and uid
689      attributes as a filter.
690
691   o  Base searches at either entry of the second tier.
692
693   o  One-level and sub-tree searches at either entry of the second
694      tier, using cn or uid attributes as a filter.
695
696   o  Base, one-level, and sub-tree searches based at any contact or
697      name server entry and below.
698
6995.  Clients
700
701   Early scoping and analysis of this project were based on the use of
702   output from command line clients, specifically the "ldapsearch"
703   command present with many implementations of LDAP servers.  Our
704   survey of this tool, available from many vendors, showed that
705   referral chasing was difficult to control or predict, and the
706   behavior between these implementations with respect to referral
707   chasing was inconsistent.
708
709   Based on the limited nature of the expressive capabilities present
710   with just command line tools, searches involving nested queries or
711   advanced referral chasing were deemed the domain of clients making
712   direct use of LDAP client libraries.  Three of these types of clients
713   were produced: a web-based client, a cross-platform C-based client,
714   and a Java client.  No significant deficiencies or problems were
715   found with the LDAP client libraries in the construction of these
716   clients, and the level of control provided by their programming
717   interfaces was adequate to create the necessary searches.  Instead,
718   most of the problems encountered with these clients were based on
719   usability concerns.
720
721   It was found that the web-based client caused a great amount of
722   confusion for users not familiar with LDAP or Nicname/Whois with
723   respect to the underlying technology and the network model.  Thus,
724   many users believed the web-based client to be the only interface to
725   the data and were unaware or confused by the intermediate LDAP
726   protocol.  In addition, it was difficult to express to users the
727
728
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734
735   registry-registrar-registrant service model in adequate terms from
736   search results where the results could be rendered properly among the
737   various common web browsers.
738
739   Both the C and Java based clients were built to be both graphical and
740   cross-platform (in the case of the C-based client, the Linux and
741   Windows platforms were chosen as targets).  The LDAP client libraries
742   chosen for both clients proved to be quite capable and offered the
743   necessary levels of control for conducting nested queries and
744   advanced referral chasing.  Expectations at the outset for
745   construction of both clients, based on past experience, were that the
746   C-based client would not only perform better than the Java client but
747   also have a better appearance.  In reality, these assumptions were
748   incorrect as there was no perceivable difference in performance and
749   the look of the Java client was often considered to be far superior
750   to its counter-part.  In addition, the Java client required much less
751   time to create.  Both clients are available under the terms of an
752   open source license.  Though it is impossible to have accurate
753   measurements of their popularity, through monitoring and feedback it
754   was perceived that the web-based client had far greater use.
755
7566.  Lessons Learned
757
758   Based on the experience of piloting this experimental service,
759   feedback from users of the service, and general comments and
760   observations of current and common opinions, the following items have
761   been noted.
762
7636.1.  Intra-Server Referrals
764
765   Original analysis of the data set to be used revealed a high degree
766   of relationships between name servers, contacts, and domains.
767   Storing the data in non-normalized form according to the DIT outlined
768   in this document would make an original relational dataset of roughly
769   20 million objects explode to over 115 million objects.
770
771   To combat this problem, the first pass at defining the DIT's made
772   heavy use of referrals between the TLD DIT's and the name server and
773   contact DIT's.  The use of the 'alias' objectclass was considered but
774   ruled out in hopes of using referrals for load balancing across
775   servers (i.e., placing each TLD DIT on a separate server, and
776   separate servers for the name server and contact DIT's).  However,
777   initial testing with the 'ldapsearch' command found inconsistencies
778   with the interpretation of the referrals and how they were managed.
779   Not only were the results inconsistent between implementations, but
780   many of these clients would easily get caught in referral loops.
781
782
783
784
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790
791   The final solution to the problem was to create a customized back-end
792   data store containing the data in a normalized form.  This gave the
793   client the appearance of having a non-normalized data set which
794   required no intra-server referrals.  Aliases may have been a better
795   solution, however our interpretation of their output with
796   implementations of the 'ldapsearch' tool was not satisfactory.  It
797   was also later learned that some LDAP server implementations place
798   certain restrictions on aliases that would have conflicted with our
799   overall DIT structure.  In the end, it was felt that a customized
800   back-end would be required by any server with a large data-set, but
801   smaller data-sets for less populated domains could easily use off-
802   the-shelf implementations.
803
8046.2.  Inter-Server Referrals
805
806   The modeling of the overall service to provide the split in
807   operational responsibility between registry and registrar required
808   the use of referrals (i.e., the two servers would not be operated by
809   the same organization, therefore would most likely not co-exist on
810   the same physical machine or network).  The chief problem with LDAP
811   referrals returned for this purpose grew out of the need to limit
812   data returned to the client and the priority given to referrals.  It
813   was quite easy to cause a sub-tree query at certain levels, for
814   instance a TLD level, to return nothing but referrals.  This was true
815   because referrals would be returned out of the scope of the supplied
816   search filter and therefore would fill the result set to its limit,
817   normally set to 50 entries.
818
819   In certain use cases, a result set with nothing but referrals was
820   desired (e.g., o=tlds).  However, even in these cases it was possible
821   for some referrals to not be returned due to the size limit.  In this
822   case, it was felt that a result set of 50 referrals, the default for
823   the size limit in most cases, was too large for any practical use by
824   a client and was a failing of query distribution in general rather
825   than a limitation of LDAP.
826
8276.3.  Common DIT
828
829   Because of the nature of software development, the graphical and web
830   clients were developed after the development of the server software.
831   The 'ldapsearch' client was used for testing and development during
832   server software creation.  It was not until the creation of more
833   advanced clients that it was discovered that the design decision of
834   uniform DIT naming should have been made.  Technically, this would
835   have allowed for slightly better software modularization and re-use.
836   In addition, the use of a company name in the DIT structure did not
837   allow the easy integration of another domain registry, as in the
838   registry-registrar model.  Not only would clients have to be
839
840
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846
847   reconfigured for each new registry operator, but this would most
848   likely have social implications as well.
849
8506.4.  Universal Client
851
852   The construction of the clients revealed yet another misconception.
853   Though this project used a generic directory service technology, the
854   clients required a high-degree of algorithmic knowledge about the DIT
855   structure and schemas being used.  The graphical clients could not be
856   used against an LDAP service with another DIT or schema.  Therefore,
857   a generic or universal client, one that could be used for all LDAP
858   applications, would either not be able to make full use of the data
859   provided by the service or would be far too complex for operation by
860   the average user.
861
8626.5.  Targeting Searches by Tier
863
864   The network model for this service was divided into three tiers:
865   registry, registrar, and registrant.  Despite this, all searches
866   needed to start at the registry level causing overhead for searches
867   that could be targeted at a select tier.  This service did not
868   implement a solution to this problem, such as using SRV and/or NAPTR
869   records in DNS to allow a client to find a responsible LDAP server.
870
8716.6.  Data Mining
872
873   Section 3.1.2 and Section 4.1.2 describe the searches allowed by this
874   service.  However, the most common question asked by users of the
875   service revolved around getting around these restrictions.  Because
876   browsing at the TLD level was not permitted, many users asked about
877   the feasibility of using recursive dictionary queries to circumvent
878   the search restrictions.
879
880   It should be noted that many operators of Nicname/Whois server
881   consider this practice to be data mining and often refer to it
882   specifically as a dictionary attack.
883
8847.  IANA Considerations
885
886   There are no applicable IANA considerations presented in this
887   document.
888
8898.  Internationalization Considerations
890
891   The domain administrative data in this service did not cover
892   Internationalized Domain Names (IDN's).
893
894
895
896
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902
9039.  Security Considerations
904
905   This experiment did not endeavor to use security mechanisms beyond
906   those readily available in LDAP [5].  Section 3.1.3 and Section 4.1.3
907   describe the various access controls used within the scope of the
908   defined security mechanisms.   While these mechanisms were adequate
909   for this experimental deployment, they would not be adequate for a
910   production environment, and they should not be taken as a model for
911   those contemplating deployment on the Internet.
912
91310.  Intellectual Property Statement
914
915   The IETF takes no position regarding the validity or scope of any
916   intellectual property or other rights that might be claimed to
917   pertain to the implementation or use of the technology described in
918   this document or the extent to which any license under such rights
919   might or might not be available; neither does it represent that it
920   has made any effort to identify any such rights.  Information on the
921   IETF's procedures with respect to rights in standards-track and
922   standards-related documentation can be found in BCP-11.  Copies of
923   claims of rights made available for publication and any assurances of
924   licenses to be made available, or the result of an attempt made to
925   obtain a general license or permission for the use of such
926   proprietary rights by implementors or users of this specification can
927   be obtained from the IETF Secretariat.
928
929   The IETF invites any interested party to bring to its attention any
930   copyrights, patents or patent applications, or other proprietary
931   rights which may cover technology that may be required to practice
932   this standard.  Please address the information to the IETF Executive
933   Director.
934
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936
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958
95911.  Normative References
960
961   [1]  Harrenstien, K., Stahl, M. and E. Feinler, "NICNAME/WHOIS", RFC
962        954, October 1985.
963
964   [2]  Barker, P., Kille, S. and T. Lenggenhager, "Naming and
965        Structuring Guidelines for X.500 Directory Pilots", RFC 1617,
966        May 1994.
967
968   [3]  Williamson, S., Kosters, M., Blacka, D., Singh, J. and K.
969        Zeilstra, "Referral Whois (RWhois) Protocol V1.5", RFC 2167,
970        June 1997.
971
972   [4]  Kille, S., Wahl, M., Grimstad, A., Huber, R. and S. Sataluri,
973        "Using Domains in LDAP/X.500 Distinguished Names", RFC 2247,
974        January 1998.
975
976   [5]  Wahl, M., Howes, T. and S. Kille, "Lightweight Directory Access
977        Protocol (v3)", RFC 2251, December 1997.
978
979   [6]  Wahl, M., Coulbeck, A., Howes, T. and S. Kille, "Lightweight
980        Directory Access Protocol (v3): Attribute Syntax Definitions",
981        RFC 2252, December 1997.
982
983   [7]  Wahl, M., "A Summary of the X.500(96) User Schema for use with
984        LDAPv3", RFC 2256, December 1997.
985
986   [8]  Howard, L., "An Approach for Using LDAP as a Network Information
987        Service", RFC 2307, March 1998.
988
989   [9]  Smith, M., "Definition of the inetOrgPerson LDAP Object Class",
990        RFC 2798, April 2000.
991
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1014
1015Appendix A.  Other Work
1016
1017   In addition to the deployment of servers and development of clients,
1018   VeriSign conducted two sub-projects related to this experiment.
1019
1020   The first project was a Nicname/Whois-to-LDAP gateway.  The goal of
1021   the project was to create an LDAP server for use by registrars to
1022   deploy in front of their Nicname/Whois servers.  This gateway would
1023   take LDAP requests, translate them to Nicname/Whois requests, issue
1024   the request to a specific Nicname/Whois server deployed on port 43,
1025   interpret the response, and return LDAP result sets.  Because of the
1026   unspecified nature of Nicname/Whois result sets, the gateway was
1027   programmed to specifically recognize only the output of three
1028   distinct registrars.  While this gateway proved valuable enough to
1029   allow domain lookups and limited searches, it was unable to provide
1030   consistent contact lookups, nameserver lookups, or registrant
1031   referrals.  This software was also made publicly available under the
1032   terms of an open source license.
1033
1034   The second project was an informal survey of registrants with
1035   deployed LDAP servers.  This was conducted by using the com, net,
1036   org, and edu zone files and testing for the existence of an LDAP
1037   server on port 389 using the name of the domain, a host named "ldap"
1038   in the domain, and a host named "dir" in the domain (e.g., "foo.com",
1039   "ldap.foo.com", and "dir.foo.com").  This survey did not attempt to
1040   resolve LDAP services using SRV records in DNS.
1041
1042   The result of this survey found that roughly 0.5% of active domains
1043   had an LDAP server.  By profiling a server's root DSA-specific Entry
1044   (DSE), the survey found that about 90% of the servers were
1045   implementations provided by vendor A, 9% of the servers were
1046   implementations provided by vendor B, and 1% of the servers were
1047   implementations provided by other vendors.  Of the servers queried
1048   that were determined to be implementations provided by vendor A, it
1049   appeared that about only 10% contained public data (this also led to
1050   the assumption that the other 90% were not intended to be publicly
1051   queried).  Of the servers queried that were determined to be
1052   implementations provided by vendor B, it appears that nearly all
1053   contained public data.
1054
1055Appendix B.  Acknowledgments
1056
1057   Significant analysis, design, and implementation for this project
1058   were conducted by Brad McMillen, David Blacka, Anna Zhang, and
1059   Michael Schiraldi.  Mark Kosters and Leslie Daigle provided guidance
1060   by reviewing this project, the project's goals, and this document.
1061
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1070
1071Author's Address
1072
1073   Andrew Newton
1074   VeriSign, Inc.
1075   21345 Ridgetop Circle
1076   Sterling, VA  20166
1077   USA
1078
1079   Phone: +1 703 948 3382
1080   EMail: anewton@verisignlabs.com; anewton@ecotroph.net
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1127Full Copyright Statement
1128
1129   Copyright (C) The Internet Society (2003).  All Rights Reserved.
1130
1131   This document and translations of it may be copied and furnished to
1132   others, and derivative works that comment on or otherwise explain it
1133   or assist in its implementation may be prepared, copied, published
1134   and distributed, in whole or in part, without restriction of any
1135   kind, provided that the above copyright notice and this paragraph are
1136   included on all such copies and derivative works.  However, this
1137   document itself may not be modified in any way, such as by removing
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1140   developing Internet standards in which case the procedures for
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1142   followed, or as required to translate it into languages other than
1143   English.
1144
1145   The limited permissions granted above are perpetual and will not be
1146   revoked by the Internet Society or its successors or assignees.
1147
1148   This document and the information contained herein is provided on an
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1150   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
1151   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
1152   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
1153   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
1154
1155Acknowledgement
1156
1157   Funding for the RFC Editor function is currently provided by the
1158   Internet Society.
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